JP6790940B2 - Sensor abnormality diagnostic device - Google Patents

Description

The present invention relates to a sensor abnormality diagnostic device.

Conventionally, as seen in Patent Document 1, an in-vehicle system including a rotary electric machine as a traveling power source of a vehicle and two current sensors for detecting phase currents at the same location flowing through the rotary electric machine is known. This system is equipped with a control device for diagnosing an abnormality in one of the two current sensors by comparing the detected values of the two current sensors.

Japanese Unexamined Patent Publication No. 2007-185043

The control device diagnoses the presence or absence of an abnormality in the current sensor when the rotary electric machine is driven and the vehicle is running. Here, if it is diagnosed that an abnormality has occurred in the current sensor while the vehicle is running, for example, the drive control of the rotary electric machine is stopped and the vehicle cannot be run properly. In this case, the convenience of the vehicle user may be reduced.

It should be noted that the system that can reduce the convenience of the user when it is diagnosed that an abnormality has occurred in the current sensor is not limited to the system installed in the vehicle. Further, the sensor to be diagnosed with an abnormality is not limited to the current sensor.

A main object of the present invention is to provide a sensor abnormality diagnosis device capable of appropriately diagnosing a sensor abnormality so as not to reduce the convenience of a system user.

The present invention is applied to a system including a boost converter that boosts and outputs a voltage input from a power supply, wherein the boost converter has a reactor that can be connected to the power supply and a smoothing that is connected to the output side of the boost converter. The system includes a capacitor, a current sensor that detects a current value flowing through the reactor, and a voltage sensor that detects a voltage value of the smoothing capacitor, and is an estimated value of the voltage value of the smoothing capacitor. A voltage estimated value, a current detected value which is a current value detected by the current sensor, a voltage detected value which is a voltage value detected by the voltage sensor, or a current estimated value which is an estimated value of a current value flowing through the reactor. The voltage detection value and the current detection value are defined as a sensor estimation value, an estimation detection value, and a diagnosis detection value, respectively.

The present invention includes a precharge unit that performs a process of charging the smoothing capacitor from the power source via the reactor when the system is started, and the estimated detection value during the charging period of the smoothing capacitor by the precharge unit. Based on the change in the sensor, the estimated value calculation unit that calculates the sensor estimated value, the calculated sensor estimated value, and the diagnostic detection value, either the current sensor or the voltage sensor. It is provided with a diagnostic unit for diagnosing an abnormality in the capacitor.

The system to which the present invention is applied includes a boost converter. The boost converter includes a reactor and a smoothing capacitor. Here, in order to suppress the deterioration of the convenience of the user of the system, it is desirable that the abnormality diagnosis of the sensor is performed before the user starts to use the system.

Therefore, in the present invention, the charging process of the smoothing capacitor performed by the precharging unit at the start of the system is used for the abnormality diagnosis of the sensor. Specifically, the sensor estimated value, the estimated detected value, and the diagnostic detected value are defined as described above. The estimated value calculation unit calculates the sensor estimated value based on the change in the detected value for estimation during the charging period of the smoothing capacitor. The degree of discrepancy between the sensor estimation value and the diagnostic detection value differs depending on whether an abnormality has occurred in either the current sensor or the voltage sensor or in neither the current sensor nor the voltage sensor. Therefore, at the time of system startup, the diagnostic unit diagnoses that an abnormality has occurred in either the current sensor or the voltage sensor based on the comparison between the calculated sensor estimated value and the diagnostic detection value. Can be done. According to the present invention described above, it is possible to properly diagnose the abnormality of the sensor so as not to reduce the convenience of the user of the system.

The overall block diagram of the motor control system which concerns on 1st Embodiment. The block diagram which shows the output voltage control processing of a boost converter. The figure for demonstrating the time ratio. A time chart showing the transition of the bus voltage detection value during precharging. The flowchart which shows the procedure of the sensor abnormality diagnosis processing. The flowchart which shows the procedure of the sensor abnormality diagnosis processing which concerns on 3rd Embodiment. Above, a time chart showing the transition of the lower limit voltage estimate. A time chart showing a transition of a bus voltage detection value and the like at the time of precharging according to the fourth embodiment. The flowchart which shows the procedure of the sensor abnormality diagnosis processing which concerns on 5th Embodiment. A time chart showing the transition of the reactor current estimated value during precharging. The flowchart which shows the procedure of the sensor abnormality diagnosis processing which concerns on 6th Embodiment. The overall block diagram of the motor control system which concerns on 7th Embodiment. The overall block diagram of the motor control system which concerns on 8th Embodiment.

(First Embodiment)
Hereinafter, a first embodiment embodying the abnormality diagnostic apparatus according to the present invention will be described with reference to the drawings. In the present embodiment, the abnormality diagnosis device is mounted on a vehicle such as an electric vehicle or a hybrid vehicle provided with a rotating electric machine as an in-vehicle main engine.

As shown in FIG. 1, the vehicle-mounted control system includes a battery 10 as a DC power source, a boost converter 20, an inverter 30, a motor generator 40, and a control device 50. The battery 10 is a rechargeable power storage device. In the present embodiment, the motor generator 40 is an in-vehicle main engine, and its rotor is capable of transmitting power to drive wheels (not shown). As the motor generator 40, for example, a synchronous machine having a permanent magnet in the rotor can be used. The battery 10 and the boost converter 20 constitute a power supply system.

The boost converter 20 includes a reactor 21, a smoothing capacitor 22, an upper arm transformer switch Scp, and a lower arm transformer switch Scn. The boost converter 20 has a function of boosting the output voltage of the battery 10 up to a predetermined voltage. In the present embodiment, each transformer switch Scp, Scn is a voltage-controlled semiconductor switching element, specifically an IGBT. Freewheel diodes Dcp and Dcn are connected in antiparallel to each transformer switch Scp and Scn.

A positive electrode bus Lp is connected to a collector which is a terminal on the high potential side of the upper arm transformer switch SCP. The collector of the lower arm transformer switch Scn is connected to the emitter which is the low potential side terminal of the upper arm transformer switch Scp. A negative electrode bus Ln is connected to the emitter of the lower arm transformer switch Scn. Each bus Lp, Ln is composed of, for example, a bus bar.

A smoothing capacitor 22 is connected in parallel to the series connection body of the upper arm transformer switch Scp and the lower arm transformer switch SCP. The first end of the reactor 21 is connected to the connection point between the upper arm transformer switch Scp and the lower arm transformer switch SCP. A positive electrode terminal of the battery 10 is connected to the second end of the reactor 21. The emitter of the lower arm transformer switch Scn is connected to the negative electrode terminal of the battery 10.

The input side of the inverter 30 is connected to the positive electrode bus Lp and the negative electrode bus Ln. The inverter 30 includes a series connection body of the upper arm switches Sup, Sbp, Swp and the lower arm switches Sun, Svn, Swn for three phases. In the present embodiment, each switch Sup, Sun, Sbp, Svn, Swp, Swn is a voltage-controlled semiconductor switching element, and more specifically, an IGBT. Freewheel diodes Dup, Dun, Dbp, Dvn, Dwp, and Dwn are connected in antiparallel to each switch Sup, Sun, Spp, Svn, Swp, and Swn.

A positive electrode bus Lp is connected to a collector which is a terminal on the high potential side of each of the upper arm switches SUP, Svp, and Swp. A negative electrode bus Ln is connected to an emitter which is a low potential side terminal of each of the lower arm switches Sun, Svn, and Swn.

The first end of the U-phase winding 40U of the motor generator 40 is connected to the connection points of the U-phase upper and lower arm switches Sup and Sun. The first end of the V-phase winding 40V of the motor generator 40 is connected to the connection points of the V-phase upper and lower arm switches Svp and Svn. The first end of the W-phase winding 40W of the motor generator 40 is connected to the connection points of the W-phase upper and lower arm switches Swp and Swn. The second ends of each phase winding 40U, 40V, 40W are connected at the neutral point. The U, V, and W phase windings 40U, 40V, and 40W are offset by 120 ° from each other in terms of electrical angle.

The control system includes a relay 41 as a switch unit. In the present embodiment, the relay 41 is provided outside the boost converter 20 in the electric path connecting the positive electrode terminal of the battery 10 and the second end of the reactor 21. When the relay 41 is opened, the battery 10 and the boost converter 20 are electrically cut off. On the other hand, when the relay 41 is closed, the battery 10 and the boost converter 20 are in an electrically conductive state. The relay 41 may be opened / closed by the control device 50, or may be opened / closed by another control device which is a control device different from the control device 50. When a configuration in which the relay 41 is opened / closed by another control device is adopted, the control device 50 may perform a process of instructing another control device, for example, an opening / closing operation command of the relay 41.

The control system includes a reactor current sensor 60, an input voltage sensor 61, an output voltage sensor 62, a phase current sensor 63, and a rotation position sensor 64. The reactor current sensor 60 detects the current value flowing through the reactor 21 as the reactor current detection value ILr. The input voltage sensor 61 detects the input voltage of the boost converter 20 as the input voltage detection value Vin. The output voltage sensor 62 detects the voltage between the terminals of the smoothing capacitor 22 as the bus voltage detection value Vsys. The phase current sensor 63 detects the phase currents of at least two of the U, V, and W phases. The rotation position sensor 64 is, for example, a resolver, and detects the rotation position of the rotor of the motor generator 40.

The detected value of each sensor is input to the control device 50. The control device 50 is mainly composed of a microcomputer, and operates a boost converter 20 and an inverter 30 in order to control the control amount of the motor generator 40 to the command value thereof. In the present embodiment, the control amount is torque and the command value is command torque.

The control device 50 turns on / off the transformer switches Scpp and Scn constituting the boost converter 20 in order to feedback-control the bus voltage detection value Vsys detected by the output voltage sensor 62 to the target voltage value Vtgt. In the present embodiment, the upper arm transformer switch Scp and the lower arm transformer switch SCP are alternately turned on with a dead time in between.

The control device 50 turns on / off the switches Sup, Sun, Spp, Swn, Swp, Swn of the inverter 30 based on the detected values of the phase current sensor 63 and the rotation position sensor 64. The upper arm switches Sup, Sbp, Swp and the corresponding lower arm switches Sun, Svn, Swn are alternately turned on with a dead time in between.

Subsequently, the process related to the boost converter 20 among the processes performed by the control device 50 will be described with reference to FIG. In the present embodiment, among both ends of the reactor 21, the current value flowing in the direction from the positive electrode terminal side of the battery 10 toward the connection point side of each transformer switch Scp and Scn is defined as positive. Further, in the present embodiment, the process shown in FIG. 2 is performed after the precharge process described later is completed.

The voltage deviation calculation unit 51 calculates the voltage deviation ΔV as a value obtained by subtracting the bus voltage detection value Vsys from the target voltage value Vtgt.

The voltage FB control unit 52 sets a target current value ILtgt, which is a target value of the current value flowing through the reactor 21, as an operation amount for feedback-controlling the bus voltage detection value Vsys to the target voltage value Vtgt based on the voltage deviation ΔV. calculate. In the present embodiment, the feedback control used by the voltage FB control unit 52 is proportional integration control.

The current deviation calculation unit 53 calculates the current deviation ΔI as a value obtained by subtracting the reactor current detection value ILr from the target current value ILtgt.

The current FB control unit 54 calculates the time ratio duty as an operation amount for feedback-controlling the reactor current detection value ILr to the target current value ILtgt based on the current deviation ΔI. In the present embodiment, the feedback control used by the current FB control unit 54 is proportional integration control. As shown in FIG. 3, the time ratio duty is the ratio of the on-operation time Ton to one switching cycle Tsw of the lower arm transformer switch Scn. In FIG. 3, the dead time is set to 0.

The control device 50 alternately turns on the upper arm transformer switch Scp and the lower arm transformer switch Scn based on the calculated time ratio duty. Specifically, for example, the control device 50 generates operation signals for the upper and lower arm transformation switches Scp and Scn by PWM processing based on the time ratio Duty and the magnitude comparison of the carrier signals, and moves up based on the generated operation signals. The arm transformation switch Scp and the lower arm transformation switch Scn are alternately turned on.

The control device 50 performs a precharge process for switching the relay 41 from the open state to the closed state when the control system is started. When the relay 41 is switched to the closed state, a charging current is supplied from the battery 10 to the smoothing capacitor 22 via the reactor 21 and the freewheel diode Dcp. As a result, electric charge is accumulated in the smoothing capacitor 22. By the way, the time when the control system is activated is, for example, the time when the operating member for making the vehicle travelable is operated by the user. Specifically, for example, the operating member is an ignition switch or a start switch. The user turns on the ignition switch or the start switch to enable the vehicle to travel.

FIG. 4 shows the operating state of the relay 41 during the precharge process, the transition of the current value actually flowing through the reactor 21, and the transition of the bus voltage detection value Vsys. In the present embodiment, the control device 50 performs the precharge process for a period from the timing when the relay 41 is switched to the closed state to the timing when the threshold time Tth elapses. FIG. 4 shows the start timing of the precharge process at time t1, the completion timing of the precharge process at time t2, and the bus voltage detection value Vsys at the completion timing of the precharge process at the completion detection value Vsys0. Shown.

The control device 50 performs an abnormality diagnosis process for diagnosing whether or not an abnormality has occurred in either the reactor current sensor 60 or the output voltage sensor 62 during the period in which the precharge process is performed.

FIG. 5 shows the procedure of the abnormality diagnosis processing according to the present embodiment. This process is executed by the control device 50.

First, in step S10, prior to the start of the precharge process, the learning process of the offset error Ioff included in the reactor current detection value ILr is performed. The offset error If is an error in which the reactor current detection value ILr always deviates from the current value actually flowing through the reactor 21 by a specified value. Specifically, in step S10, the reactor current detection value ILr when the relay 41 is in the open state is learned as the offset error If. In this embodiment, the process of step S10 corresponds to the learning unit.

In the following step S11, it is determined whether or not the absolute value of the learned offset error If is less than the predetermined value Iα. This process is a process for determining whether or not the estimation accuracy of the bus voltage estimated value Best, which is the estimated value of the inter-terminal voltage of the smoothing capacitor 22, can be maintained. If it is determined in step S11 that the absolute value of the offset error If is less than the predetermined value Iα, the process proceeds to step S12. On the other hand, if it is determined in step S11 that the absolute value of the offset error If is equal to or greater than the predetermined value Iα, the process proceeds to step S19, and the abnormality diagnosis process is prohibited.

Incidentally, in the present embodiment, when a negative determination is made in step S11, the boost converter 20 and the inverter 30 are operated so as to maintain the stopped state of the motor generator 40. This makes it impossible to use the motor generator 40 as a traveling power source for the vehicle.

In step S12, prior to the start of the precharge process, it is determined whether or not the bus voltage detection value Vsys is less than the predetermined voltage value Vα. This process is a process for determining whether or not the estimation accuracy of the bus voltage estimated value Vest can be maintained. If it is determined in step S12 that the bus voltage detection value Vsys is less than the predetermined voltage value Vα, it is determined that the electric charge is completely discharged from the smoothing capacitor 22, and the process proceeds to step S13. On the other hand, when it is determined in step S12 that the bus voltage detection value Vsys is equal to or higher than the predetermined voltage value Vα, it is determined that electric charge is accumulated in the smoothing capacitor 22, and the process proceeds to step S19 to prohibit the abnormality diagnosis process. .. The predetermined voltage value Vα may be set to a value capable of determining that the electric charge is completely discharged from the smoothing capacitor 22 based on the detection error included in the bus voltage detection value Vsys, for example.

In step S13, the relay 41 is switched from the open state to the closed state to start the precharge process. In this embodiment, the process of step S13 corresponds to the precharge unit.

In the following steps S14 and S15, the bus voltage estimated value Best is calculated based on the reactor current detection value "ILr-Off" corrected by the learned offset error Ifoff and the following equation (eq1).

上式（ｅｑ１）において、Ｃは平滑コンデンサ２２の静電容量を示し、Ｔαは積分時間を示す。本実施形態において、積分時間Ｔαは上記閾値時間Ｔｔｈに設定されている。ステップＳ１４，Ｓ１５の処理によれば、プリチャージ処理の開始タイミングから、この開始タイミングから閾値時間Ｔｔｈ経過するタイミングまでにおける「ＩＬｒ−Ｉｏｆｆ」の積算値に基づいて、プリチャージ処理の完了タイミングにおける母線電圧推定値Ｖｅｓｔが算出される。なお本実施形態において、ステップＳ１４，Ｓ１５の処理が推定値算出部に相当する。また本実施形態において、母線電圧推定値Ｖｅｓｔがセンサ推定値に相当し、リアクトル電流検出値ＩＬｒが推定用検出値に相当する。

In the above equation (eq1), C indicates the capacitance of the smoothing capacitor 22, and Tα indicates the integration time. In the present embodiment, the integration time Tα is set to the above threshold time Tth. According to the processes of steps S14 and S15, the bus at the completion timing of the precharge process is based on the integrated value of "ILr-Ioff" from the start timing of the precharge process to the timing when the threshold time Tth elapses from this start timing. The voltage estimate vest is calculated. In this embodiment, the processes of steps S14 and S15 correspond to the estimated value calculation unit. Further, in the present embodiment, the bus voltage estimated value Best corresponds to the sensor estimated value, and the reactor current detected value ILr corresponds to the estimated detected value.

In the following step S16, it is determined whether or not the absolute value of the difference between the bus voltage estimated value Vest at the completion timing of the precharge process and the bus voltage detection value Vsys at the completion timing of the precharge process is larger than the predetermined potential difference ΔVth. .. This process is a process for determining whether or not an abnormality has occurred in either the reactor current sensor 60 or the output voltage sensor 62. That is, the degree of deviation between the bus voltage estimated value Vest and the bus voltage detection value Vsys when an abnormality has occurred in either the reactor current sensor 60 or the output voltage sensor 62 and when no abnormality has occurred in either of them. Is different. The predetermined potential difference ΔVth is set based on, for example, a detection error included in the reactor current detection value ILr, a detection error included in the bus voltage detection value Vsys, and a variation in the capacitance C of the smoothing capacitor 22. In this embodiment, the bus voltage detection value Vsys corresponds to the diagnostic detection value.

If a negative determination is made in step S16, the process proceeds to step S17, and it is diagnosed that neither the reactor current sensor 60 nor the output voltage sensor 62 has an abnormality. On the other hand, if an affirmative determination is made in step S16, it is determined that the degree of deviation between the bus voltage estimated value Vest and the bus voltage detection value Vsys is large, and the process proceeds to step S18. In step S18, it is diagnosed that an abnormality has occurred in either the reactor current sensor 60 or the output voltage sensor 62. In the present embodiment, when it is diagnosed that an abnormality has occurred, a process of stopping the operation of the boost converter 20 and the inverter 30 is performed in order to stop the driving of the motor generator 40. As a result, torque is no longer output from the motor generator 40 to the drive wheels of the vehicle. Further, in the present embodiment, the processes of steps S16 and S18 correspond to the diagnostic unit.

By the way, the process of step S15 may be replaced with the process of determining whether or not the bus voltage detection value Vsys has reached the input voltage detection value Vin. In this case, the precharge process is completed when the bus voltage detection value Vsys matches the input voltage detection value Vin.

According to the present embodiment described in detail above, the following effects can be obtained.

Abnormality diagnosis processing is performed during precharging processing that is performed when the control system is started. As a result, even if it is diagnosed that an abnormality has occurred in either the reactor current sensor 60 or the output voltage sensor 62 by the abnormality diagnosis process, the vehicle user can grasp the diagnosis result before the vehicle travels. Therefore, the user can take countermeasures against abnormalities such as requesting repair of the vehicle before running the vehicle. As a result, it is possible to suppress a decrease in user convenience.

The bus voltage estimated value Best is calculated based on the integrated value of the reactor current detection value ILr. In this configuration, since the differential value of the sensor detection value is not used, the resistance to noise is high. Therefore, the estimation accuracy of the voltage between the terminals of the smoothing capacitor 22 can be improved, and the abnormality diagnosis accuracy can be improved.

When it is determined that the bus voltage detection value Vsys before the start of the precharge process is less than the predetermined voltage value Vα, the abnormality diagnosis process is performed. Therefore, it is possible to suppress the influence of the detection error that may be included in the bus voltage detection value Vsys at the start timing of the precharge process on the setting of the predetermined potential difference ΔVth in step S16.

When it is determined that the absolute value of the offset error Ioff is equal to or greater than the predetermined value Iα, the abnormality diagnosis process is prohibited. When the offset error If is large, the reactor current sensor 60 is in an abnormal state, so that the stopped state of the motor generator 40 is maintained. In such a state, the control device 50 does not need to perform the abnormality diagnosis process. Therefore, according to the present embodiment, it is possible to prevent the control device 50 from performing unnecessary processing.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In the present embodiment, in step S14 of FIG. 5 above, the integration time Tα is set to a time shorter than the threshold time Tth. Therefore, by the processing of steps S14 and S15, the bus voltage estimated value Best before the precharging processing is completed is calculated.

In the following step S16, it is determined whether or not the absolute value of the difference between the bus voltage estimated value Vest before the completion of the precharge process and the bus voltage detection value Vsys before the completion of the precharge process is larger than the predetermined potential difference ΔVth. ..

According to the present embodiment described above, the abnormality diagnosis process can be started earlier than that of the first embodiment.

(Third Embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, the abnormality diagnosis method is changed.

FIG. 6 shows the procedure of the abnormality diagnosis processing according to the present embodiment. This process is executed by the control device 50. In FIG. 6, the same step numbers are assigned to the same processes as those shown in FIG. 5 above for convenience.

After the processing of step S13 is completed, in steps S20 and S15, the bus voltage estimated value Vest is taken based on the upper limit current detection value ILrU, which is the upper limit value that the reactor current detection value ILr can take, and the following equation (eq2). The upper limit voltage estimated value BestU, which is the upper limit value to be obtained, is calculated. Here, the upper limit current detection value ILrU is a value “ILr−” obtained by adding the maximum value ΔIL (> 0) of the detection error that can be included in the reactor current detection value ILr to the reactor current detection value corrected by the learned offset error Ifoff. It may be calculated as "Offset + ΔIL". In the following equation (eq2), Cmin indicates the lower limit of the possible capacitance of the smoothing capacitor 22. The capacitance of the mass-produced smoothing capacitor 22 varies from the lower limit value Cmin of the capacitance to the upper limit value Cmax of the possible capacitance of the smoothing capacitor 22.

また、ステップＳ２０，Ｓ１５では、リアクトル電流検出値ＩＬｒの取り得る下限値である下限電流検出値ＩＬｒＬと、下式（ｅｑ３）とに基づいて、母線電圧推定値Ｖｅｓｔの取り得る下限値である下限電圧推定値ＶｅｓｔＬ（＜ＶｅｓｔＵ）を算出する。ここで、下限電流検出値ＩＬｒＬは、学習したオフセット誤差Ｉｏｆｆで補正したリアクトル電流検出値から、リアクトル電流検出値ＩＬｒに含まれ得る検出誤差の最大値ΔＩＬを減算した値「ＩＬｒ−Ｉｏｆｆ−ΔＩＬ」として算出されればよい。

Further, in steps S20 and S15, the lower limit current detection value ILrL, which is the lower limit value that the reactor current detection value ILr can take, and the lower limit value that is the lower limit value that the bus voltage estimation value Vest can take, based on the following equation (eq3). The voltage estimate VestL (<VestU) is calculated. Here, the lower limit current detection value ILrL is a value “ILr-Ioff-ΔIL” obtained by subtracting the maximum value ΔIL of the detection error that can be included in the reactor current detection value ILr from the reactor current detection value corrected by the learned offset error Ioff. It may be calculated as.

ステップＳ２０，Ｓ１５の処理によれば、図７に示すように上限電圧推定値ＶｅｓｔＵ及び下限電圧推定値ＶｅｓｔＬが算出される。これにより、完了時検出値Ｖｓｙｓ０の推定範囲に幅を持たせることができる。なお本実施形態において、上限電圧推定値ＶｅｓｔＵ及び下限電圧推定値ＶｅｓｔＬがセンサ推定値に相当し、リアクトル電流検出値ＩＬｒが推定用検出値に相当する。

According to the processing of steps S20 and S15, the upper limit voltage estimated value VestU and the lower limit voltage estimated value VestL are calculated as shown in FIG. As a result, the estimated range of the detected value Vsys0 at the time of completion can be widened. In the present embodiment, the upper limit voltage estimated value VestU and the lower limit voltage estimated value VestL correspond to the sensor estimated value, and the reactor current detected value ILr corresponds to the estimated detected value.

In the following step S21, it is determined whether or not the logical sum of the first condition and the second condition is true. The first condition is that the upper limit voltage estimated value BestU at the completion timing of the precharge process is larger than the upper limit voltage detection value VsysU at the completion timing of the precharge process. The second condition is that the lower limit voltage estimated value BestL at the completion timing of the precharge process is smaller than the lower limit voltage detection value VsysL at the completion timing of the precharge process. Here, the upper limit voltage detection value VsysU is an upper limit value that the bus voltage detection value VsysU can take at the completion timing of the precharge process. The upper limit voltage detection value VsysU is, for example, a value "Vsys + ΔA" obtained by adding the maximum value ΔA (> 0) of the detection error that can be included in the bus voltage detection value Vsys to the bus voltage detection value Vsys at the completion timing of the precharge process. It may be calculated. Further, the lower limit voltage detection value VsysL (<VsysU) is a lower limit value that the bus voltage detection value Vsys can take at the completion timing of the precharge process. The lower limit voltage detection value VsysL is calculated as, for example, a value "Vsys-ΔA" obtained by subtracting the maximum value ΔA of the detection error that can be included in the bus voltage detection value Vsys from the bus voltage detection value Vsys at the completion timing of the precharge process. Just do it. In this embodiment, the bus voltage detection value Vsys corresponds to the diagnostic detection value.

If it is determined in step S21 that neither the first condition nor the second condition is satisfied, the process proceeds to step S17. On the other hand, if it is determined in step S21 that either the first condition or the second condition is satisfied, the process proceeds to step S18.

According to the present embodiment described above, the abnormality diagnosis process can be performed in consideration of the variation in the detection error included in the detection values of the sensors 60 and 62 and the variation in the capacitance of the smoothing capacitor 22.

(Fourth Embodiment)
Hereinafter, the fourth embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In the present embodiment, the control device 50 performs the abnormality diagnosis process even when the charge of the smoothing capacitor 22 is not completely discharged before the start of the precharge process for some reason. That is, as shown in FIG. 8, at the start of the precharge process, the bus voltage detection value Vsys may be set to the start detection value Voff, which is a value larger than 0. Note that FIG. 8 corresponds to FIG. 4 above.

In the present embodiment, in steps S14 and S15 of FIG. 5, the bus voltage estimated value Best is calculated based on the following equation (eq4).

ちなみに本実施形態では、図５に示す処理からステップＳ１２の処理が除去される。このため、ステップＳ１１において肯定判定した場合、ステップＳ１３に進む。

Incidentally, in the present embodiment, the process of step S12 is removed from the process shown in FIG. Therefore, if an affirmative determination is made in step S11, the process proceeds to step S13.

According to the present embodiment described above, it is possible to increase the chances of executing the abnormality diagnosis process.

(Fifth Embodiment)
Hereinafter, the fifth embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In the present embodiment, instead of the bus voltage estimated value Vest, the reactor current estimated value Irest, which is an estimated value of the current value flowing through the reactor 21, is used in the abnormality diagnosis process.

FIG. 9 shows the procedure of the abnormality diagnosis processing according to the present embodiment. This process is executed by the control device 50. Note that, in FIG. 9, the same step numbers are assigned to the same processes as those shown in FIG. 5 above for convenience.

After the processing in step S13 is completed, during the period in which the precharging processing is performed, an abnormality diagnosis is performed based on the comparison between the reactor current estimated value ILest and the reactor current detection value ILr. Specifically, in step S30, the current reactor current estimated value IREST is calculated based on the time derivative value of the bus voltage detection value Vsys, the learned offset error If, and the following equation (eq5).

図１０に、プリチャージ処理時におけるリレー４１の操作状態、リアクトル２１に実際に流れる電流値、母線電圧検出値Ｖｓｙｓ及びリアクトル電流推定値ＩＬｅｓｔの推移を示す。なお図１０には、プリチャージ処理の開始タイミングを時刻ｔ１にて示し、プリチャージ処理の完了タイミングを時刻ｔ２にて示す。なお本実施形態において、リアクトル電流推定値ＩＬｅｓｔがセンサ推定値に相当し、母線電圧検出値Ｖｓｙｓが推定用検出値に相当する。

FIG. 10 shows the operating state of the relay 41 during the precharge process, the current value actually flowing through the reactor 21, the bus voltage detection value Vsys, and the transition of the reactor current estimated value Irest. Note that FIG. 10 shows the start timing of the precharge process at time t1 and the completion timing of the precharge process at time t2. In the present embodiment, the reactor current estimated value IREST corresponds to the sensor estimated value, and the bus voltage detected value Vsys corresponds to the estimated detected value.

Returning to the explanation of FIG. 9, in the following step S31, whether or not the absolute value of the difference between the reactor current estimated value ILest calculated in step S30 and the current reactor current detection value ILr is larger than the predetermined current difference ΔIth. To judge. This process is a process for determining whether or not an abnormality has occurred in either the reactor current sensor 60 or the output voltage sensor 62. That is, the degree of deviation between the reactor current estimated value ILest and the reactor current detection value ILr depending on whether an abnormality has occurred in either the reactor current sensor 60 or the output voltage sensor 62 or no abnormality has occurred in either of them. Is different. The predetermined current difference ΔIth is set based on, for example, a detection error included in the reactor current detection value ILr, a detection error included in the bus voltage detection value Vsys, and a variation in the capacitance C of the smoothing capacitor 22. In the present embodiment, the reactor current detection value ILr corresponds to the diagnostic detection value.

If a negative determination is made in step S31, the process proceeds to step S32, and it is determined whether or not the threshold time Tth has elapsed from the start timing of the precharge process. This process is a process for determining whether or not it is the completion timing of the precharge process. If a negative determination is made in step S32, the process proceeds to step S30. On the other hand, if an affirmative determination is made in step S32, it is determined that the precharge process has been completed, and the process proceeds to step S17. If an affirmative determination is made in step S31, the process proceeds to step S18.

Incidentally, during the period in which the precharge process is performed, the control device 50 may diagnose that an abnormality has occurred when it is determined that the number of affirmative determinations in step S31 has reached a predetermined number of 2 or more.

According to the present embodiment described above, it is possible to obtain an effect similar to the effect of the first embodiment.

In the present embodiment, as in the fourth embodiment, the abnormality diagnosis process may be performed when the charge of the smoothing capacitor 22 is not completely discharged before the start of the precharge process. In this case, the process of step S12 may be removed from the process shown in FIG.

(Sixth Embodiment)
Hereinafter, the sixth embodiment will be described with reference to the drawings, focusing on the differences from the fifth embodiment. In the present embodiment, an abnormality diagnosis is performed during the precharge process.

FIG. 11 shows the procedure of the abnormality diagnosis processing according to the present embodiment. This process is executed by the control device 50. In FIG. 11, the same step numbers are assigned to the same processes as those shown in FIG. 9 above for convenience.

After the processing in step S13 is completed, in step S33, the process waits until a predetermined time Tβ (<Tth) elapses from the start timing of the precharge processing.

If an affirmative determination is made in step S33, the process proceeds to step S30. Then, in step S31, the absolute value of the difference between the reactor current estimated value ILest calculated in step S30 and the reactor current detection value ILr at the timing when the specified time Tβ has elapsed from the start timing of the precharge processing is larger than the predetermined current difference ΔIth. Judge whether or not.

According to the present embodiment described above, the abnormality diagnosis process can be performed before the precharge process is completed, as in the second embodiment.

In the present embodiment, as in the fourth embodiment, the abnormality diagnosis process may be performed when the charge of the smoothing capacitor 22 is not completely discharged before the start of the precharge process. In this case, the process of step S12 may be removed from the process shown in FIG.

(7th Embodiment)
Hereinafter, the seventh embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, as shown in FIG. 12, the control system includes an electrical load 42, a battery current sensor 65, and does not include a reactor current sensor 60. Note that, in FIG. 12, the same components as those shown in FIG. 1 above are designated by the same reference numerals for convenience.

The positive electrode terminal of the electric load 42 is connected to the reactor 21 side of the relay 41 in the electric path connecting the positive electrode terminal of the battery 10 and the second end of the reactor 21. The negative electrode terminal of the electric load 42 is connected to an electric path connecting the negative electrode terminal of the battery 10 and the emitter of the lower arm transformer switch Scn. That is, the electric load 42 is connected in parallel to the battery 10 when the relay 41 is closed. The electric load 42 includes, for example, at least one of a DCDC converter and an electric compressor. The DCDC converter steps down the output voltage of the battery 10 and supplies the stepped down voltage to another battery having an output voltage lower than that of the battery 10. The electric compressor circulates the refrigerant of the refrigeration cycle that constitutes the in-vehicle air conditioner.

The battery current sensor 65 detects the current value flowing through the battery 10 as the battery current detection value IB. During the precharge process, when the relay 41 is closed and the current value flowing through the electric load 42 is 0, the battery current sensor 65 can detect the current value flowing through the reactor 21.

In the present embodiment, the battery current detection value IB is used in the process shown in FIGS. 2 and 5 above instead of the reactor current detection value ILr. Therefore, the control device 50 can diagnose whether or not an abnormality has occurred in either the battery current sensor 65 or the output voltage sensor 62.

(8th Embodiment)
Hereinafter, the eighth embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In the present embodiment, as shown in FIG. 13, the configuration of the boost converter 20 is changed. Note that, in FIG. 13, the same components as those shown in FIG. 1 above are designated by the same reference numerals for convenience.

The boost converter 20 includes a first reactor 21a, a second reactor 21b, a smoothing capacitor 22, a first upper arm transformer switch Scap, a first lower arm transformer switch Scan, a second upper arm transformer switch Scbp, and a second lower arm transformer switch Scbn. It has.
In this embodiment, each transformer switch Scap, Scan, Scbp, Scbn is an IGBT. Freewheel diodes Dcap, Dcan, Dcbp, and Dcbn are connected in antiparallel to each of the transformer switches Scap, Scan, Scbp, and Scbn.

A positive electrode bus Lp is connected to the collectors of the first and second upper arm transformer switches Scap and Scbn. The collector of the first lower arm transformation switch Scan is connected to the emitter of the first upper arm transformation switch Scap, and the collector of the second lower arm transformation switch Scbn is connected to the emitter of the second upper arm transformation switch Scbp. There is. The negative electrode bus Ln is connected to the emitters of the first and second lower arm transformer switches Scan and Scbn.

The first end of the first reactor 21a is connected to the connection point between the first upper arm transformer switch Scap and the first lower arm transformer switch Scan, and the second upper arm transformer switch Scbp and the second lower arm transformer switch Scbn The first end of the second reactor 21b is connected to the connection point of. The positive electrode terminal of the battery 10 is connected to the second end of the first reactor 21a and the second reactor 21b. Emitters of the first and second lower arm transformer switches Scan and Scbn are connected to the negative electrode terminal of the battery 10.

The control system includes a first reactor current sensor 66a and a second reactor current sensor 66b. The first reactor current sensor 66a detects the current value flowing through the first reactor 21a as the first reactor current detection value ILr1. The second reactor current sensor 66b detects the current value flowing through the second reactor 21b as the second reactor current detection value ILr2. The detected values of the first reactor current sensor 66a and the second reactor current sensor 66b are input to the control device 50.

In the present embodiment, instead of the reactor current detection value ILr, the added values of the first reactor current detection value ILr1 and the second reactor current detection value ILr2 are used in the processes shown in FIGS. 2 and 5 above. Therefore, the control device 50 can diagnose whether or not an abnormality has occurred in any of the first reactor current sensor 66a, the second reactor current sensor 66b, or the output voltage sensor 62.

(Other embodiments)
In addition, each of the above-described embodiments may be modified as follows.

-The process of step S10 shown in FIGS. 5, 6, 9 and 11 is not essential.

-In the above equations (eq1) to (eq5), Iff = 0 may be set.

The switch unit that electrically switches between the battery 10 and the boost converter 20 to a conductive state or a cutoff state is not limited to a relay.

-The load device in which electric power is supplied from the battery 10 via the boost converter 20 is not limited to the inverter and the motor generator.

-The power source connected to the input side of the boost converter is not limited to the battery, and may be another power storage device such as a capacitor.

-The system to which the abnormality diagnosis device is applied is not limited to the system installed in the vehicle.

10 ... Battery, 20 ... Boost converter, 21 ... Reactor, 22 ... Smoothing capacitor, 50 ... Control device, 60 ... Reactor current sensor, 62 ... Output voltage sensor.

Claims (10)

It is applied to a system equipped with a boost converter (20) that boosts and outputs the voltage input from the power supply (10).
The boost converter
Reactors (21, 21a, 21b) that can be connected to the power supply
A smoothing capacitor (22) connected to the output side of the boost converter is provided.
The system
A current sensor (60, 65, 66a, 66b) that detects the value of the current flowing through the reactor, and
A voltage sensor (62) for detecting the voltage value of the smoothing capacitor is provided.
In startup before SL system, a precharge unit for performing processing for charging the smoothing capacitor from said power source through said reactor and (S13),
Estimating the voltage value of the smoothing capacitor based on the change in the current detection value (ILr, IB, ILr1, ILr2), which is the current value detected by the current sensor, during the charging period of the smoothing capacitor by the precharging unit. Estimated value calculation units (S14, S15, S20, S31) for calculating voltage estimated values (Vest, BestU, VestL), which are values, and
Based on the comparison between the calculated voltage estimation value and the voltage detection value (Vsys) which is the voltage value detected by the voltage sensor, it is determined that an abnormality has occurred in either the current sensor or the voltage sensor. A sensor abnormality diagnostic device including a diagnostic unit (S16, S18, S21, S32) for diagnosing. The estimated value calculating section (S14, S15, S20), based on the integrated value of the charging put that before Symbol current detection value in a period (ILr), calculated before Symbol estimated voltage value (Vest, VestU, VestL) a ,
The diagnostic unit (S16, S18, S21) diagnoses that an abnormality has occurred in either the current sensor or the voltage sensor based on the comparison between the calculated voltage estimation value and the voltage detection value. The sensor abnormality diagnostic device according to claim 1. The estimated value calculation unit (S20) calculates an upper limit voltage estimated value (VestU) and a lower limit voltage estimated value (VestL) smaller than the upper limit voltage estimated value as the voltage estimated value.
In the diagnostic unit (S16, S21), when the upper limit voltage estimated value is larger than the upper limit voltage detection value (VsysU) which is a possible upper limit value of the voltage detection value, or when the lower limit voltage estimated value is the voltage. The sensor abnormality according to claim 2, wherein it is diagnosed that an abnormality has occurred in either the current sensor or the voltage sensor when the detection value is smaller than the lower limit voltage detection value (VsysL) which is a possible lower limit value. Diagnostic device. The system includes a switch unit (41) that electrically switches between the power supply and the boost converter in a conductive state or a cutoff state.
The precharge unit according to any one of claims 1 to 3, wherein the smoothing capacitor is charged by switching from the cutoff state to the conduction state by the switch unit when the system is started. Sensor abnormality diagnostic device. A learning unit (S10) for learning an offset error (Ioff) included in the current detection value is provided before the switch unit switches from the cutoff state to the conduction state.
The sensor abnormality diagnosis device according to claim 4, wherein the estimated value calculation unit corrects the current detection value used for calculating the voltage estimated value based on the learned offset error. The sensor abnormality diagnosis device according to claim 5, wherein the diagnosis unit prohibits diagnosing the abnormality when the learned absolute value of the offset error is equal to or more than a predetermined value (Iα). It is applied to a system equipped with a boost converter (20) that boosts and outputs the voltage input from the power supply (10).
The boost converter
Reactors (21,21a, 21b) that can be connected to the power supply
A smoothing capacitor (22) connected to the output side of the boost converter is provided.
The system
A current sensor (60, 65, 66a, 66b) that detects the value of the current flowing through the reactor, and
A voltage sensor (62) for detecting the voltage value of the smoothing capacitor is provided.
In startup before SL system, a precharge unit for performing processing for charging the smoothing capacitor from said power source through said reactor and (S13),
A current estimated value that is an estimated value of the current value flowing through the reactor based on a change in the voltage detected value (Vsys) that is the voltage value detected by the voltage sensor during the charging period of the smoothing capacitor by the precharge unit. (Irest) calculation unit (S14, S15, S20, S31) and
Based on the comparison between the calculated current estimated value and the current detected value (ILr, IB, ILr1, ILr2) which is the current value detected by the current sensor, either the current sensor or the voltage sensor A sensor abnormality diagnostic device including a diagnostic unit (S16, S18, S21, S32) for diagnosing an abnormality. The estimated value calculation section (S31), based on the differential value of the put that before Symbol voltage detection value in the charging period (Vsys), calculated before Symbol current estimated value (ILest),
In the charging period, the diagnostic unit (S16, S32) has an abnormality in either the current sensor or the voltage sensor based on the comparison between the calculated current estimated value and the current detected value. The sensor abnormality diagnosis device according to claim 7 , wherein the sensor is diagnosed as having an abnormality. The system includes a switch unit (41) that electrically switches between the power supply and the boost converter in a conductive state or a cutoff state.
The sensor abnormality diagnosis device according to claim 8 , wherein the precharge unit performs a process of charging the smoothing capacitor by switching from the cutoff state to the conduction state by the switch unit when the system is started. 4. The diagnostic unit prohibits diagnosing the abnormality when the voltage detection value is equal to or higher than a predetermined voltage value (Vα) before the switch unit switches from the cutoff state to the conduction state. The sensor abnormality diagnostic device according to any one of items 6 and 9 .

Images